Plastics are created through a process of combining base materials like coal or crude oil and converting them (via heat) into a workable polymer. This creates 2 types of plastics: thermoplastics, which can be shaped to harden, and thermosets, which are not meltable once they have been cooled.
BPA, or bisphenol-A, is a very common chemical that's used to harden thermoset plastics and can be found almost everywhere. BPA-based plastics are super strong, light, transparent, and require extremely high heat before they melt. That’s why most of our everyday plastics have it - including baby bottles, the lining of most food and drink packages, food containers, and even our glasses.
As plastic is everywhere around us, so is BPA. Asides from it being found in the plastics we use (and being leached and absorbed by our bodies) it is also absorbed through the air, water, and dust. Because of how pervasive it is, it is estimated that 90%+ of us all have BPAs present in our bodies (they never leave our bodies, and we keep adding more).
Plastics, even microwavable plastics, are not heat-resistant. When BPA-based plastics are exposed to heat or water (like when you wash them or put anything hot/liquid in them) they begin to react with the heat or water through a process called hydrolysis. This process breaks down the bonds in the BPA and causes them to leach out of the product, into the food, the beverage ... and right into us. Either by leaching into our skin because of direct contact, or straight into our mouths when we eat or drink from these BPA-based products.
The list of health risks is pretty long, and while speculative - because there’s not been enough pressure on health institutions to do enough research - it’s key to take note and avoid them where possible.
BPA is an endocrine disruptor, and studies have shown that it can change and manipulate our hormone levels, possibly leading to cancer, heart problems, changing our reproductive system, and even our brain’s behavior.
The plastic-making process releases a lot of toxins into the atmosphere. This toxic gas that is created in and around factories negatively impacts the health of those around it - especially in residential areas that are located close by.
Apart from that, the gasses that are produced (benzene, ethylene oxide, ethylbenzene, nickel, and more) also significantly contribute to the depletion of the ozone layer and the heating of the earth.
Even worse, these factories are often involved in accidental chemical spills, explosions, fires, and fatalities.
Finally, these plastic products if they are not recycled can end up contributing to the waste and environmental pollution problem. They end up being dumped in landfills and ocean dump sites where they continue to leach BPA and other toxins, even when they break down into microplastics.